Coupling caps are usually used in circuits where only AC signals are passed through, for example, an RF amplifier has ac coupling caps at input and output, so that its dc biasing is isolated from the preceeding and subsequent circuits.
De-coupling caps, which are used to "short out" any ac component (ripple, switching noise, etc.) on the DC lines to keep DC voltages clean. Different types of caps have different frequency response, for examples, a high value cap such as 10uF tantulum caps has a much lower resonant frequency than a 100pF NPO ceramic type cap. When they are connected in parallel from DC line to ground, they "short out" a wide range of ac frequencies to keep the DC voltages clean.